Blackjack

Provably fair

Verify fairness

The session's seed decides every card. Its hash was committed before the first hand; the seed is revealed when the session ends. Each round's cards come from HMAC-SHA256 keyed by the seed over the round's number and the bettor's own seed.

Seed hash

4ec058075824588c37960e15fb60f6cb6ae253ef7008f5dcc9aa7b8a512fa876

Seed

9bdc14073a5eaf4cb7548d8a59ad6ecde723bb22ce233959ff2d01c652c00ed0 SHA-256 of "degen.match.seed.v1", a zero byte and the 32 seed bytes is the seed hash.

Bettor's seed

c66f41592142325a5e37093b5d7f3536

Commitment

Batch 56,932, Merkle root 07edb3167d03b6a756a562628ee17d4a1b150c0db0b8449a51c52ad73c24d75d. Recorded by Degen Protocol, not on a chain. See this batch and its Merkle tree

Merkle path

1. 4e2d07f901de6905565084a6488a8da3efdbb3a45fe45aab899ed9d879c80126
2. 133686ce41f11c3e78ef113d448338fdf73e3f3368552e29166927af5a7d6bad
3. 08a085691ade8404e7bec95c26baddc4875c8551a7ec4572d0668bba2fff5255

Checked: the seed hash proves into the root.

To check it yourself, take the session's proof:

1. Hash the seed as above and compare it with the seed hash; prove the seed hash into the root with the Merkle path (keccak256, as for every match).
2. For each round: round seed = HMAC-SHA256(key = seed, "degen.house.round.v1" ‖ 0x00 ‖ u64be(length of the bettor's seed) ‖ bettor's seed ‖ u64be(round)).
3. Key ChaCha20 (RFC 8439, zero nonce) with the round seed and read little-endian 64-bit words; a card is the next word below 2⁶⁴ − 1 − ((2⁶⁴ − 1) mod 52), modulo 52.
4. Replay the round's actions with the game's rules: the cards and the payout must match.

The replay plays every hand rebuilt this way on the server from the same data, and marks any that does not rebuild as recorded.